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Submission #525907

# Submission time Handle Problem Language Result Execution time Memory
525907 2022-02-13T06:53:31 Z Qingyu The Xana coup (BOI21_xanadu) C++17
100 / 100
 108 ms 56928 KB 
#include <bits/stdc++.h>

const int N = 1e6 + 50;

std::vector<int> G[N];
int a[N], dp[N][2][2], g[N][2][2], h[2][2];

void dfs(int x, int fa = 0) {
	memset(g[x], 0x3f, sizeof g[x]);
	g[x][0][0] = g[x][1][0] = 0;
	for (int y : G[x])
		if (y != fa) {
			dfs(y, x);
			memcpy(h, g[x], sizeof h);
			for (int o : {0, 1})
				for (int p : {0, 1})
					g[x][o][p] = std::min(0x3f3f3f3f, std::min(h[o][p] + dp[y][0][o], h[o][!p] + dp[y][1][o]));

		}
	for (int o : {0, 1})
		for (int p : {0, 1})
			dp[x][o][a[x] ^ o ^ p] = g[x][o][p] + o;
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	std::cout.tie(nullptr);
	int n;
	std::cin >> n;
	for (int i = 1; i < n; ++i) {
		int x, y;
		std::cin >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	for (int i = 1; i <= n; ++i) std::cin >> a[i];
	memset(dp, 0x3f, sizeof dp);
	dfs(1);
	int ans = std::min(dp[1][0][0], dp[1][1][0]);
	if (ans > n) {
		puts("impossible");
	}
	else {
		printf("%d\n", ans);
	}
	return 0;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 39392 KB Output is correct
2 Correct 16 ms 39416 KB Output is correct
3 Correct 20 ms 39444 KB Output is correct
4 Correct 18 ms 39372 KB Output is correct
5 Correct 21 ms 39372 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 39392 KB Output is correct
2 Correct 16 ms 39416 KB Output is correct
3 Correct 20 ms 39444 KB Output is correct
4 Correct 18 ms 39372 KB Output is correct
5 Correct 21 ms 39372 KB Output is correct
6 Correct 20 ms 39444 KB Output is correct
7 Correct 17 ms 39452 KB Output is correct
8 Correct 19 ms 39424 KB Output is correct
9 Correct 17 ms 39416 KB Output is correct
10 Correct 17 ms 39372 KB Output is correct
11 Correct 17 ms 39416 KB Output is correct
12 Correct 18 ms 39372 KB Output is correct
13 Correct 20 ms 39372 KB Output is correct
14 Correct 18 ms 39348 KB Output is correct
15 Correct 24 ms 39372 KB Output is correct
16 Correct 20 ms 39372 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 64 ms 56652 KB Output is correct
2 Correct 61 ms 56516 KB Output is correct
3 Correct 67 ms 56772 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 72 ms 56688 KB Output is correct
2 Correct 73 ms 56516 KB Output is correct
3 Correct 73 ms 56808 KB Output is correct
4 Correct 67 ms 45232 KB Output is correct
5 Correct 68 ms 45696 KB Output is correct
6 Correct 70 ms 45888 KB Output is correct
7 Correct 19 ms 39484 KB Output is correct
8 Correct 43 ms 41612 KB Output is correct
9 Correct 87 ms 45844 KB Output is correct
10 Correct 84 ms 45964 KB Output is correct
11 Correct 85 ms 46648 KB Output is correct
12 Correct 71 ms 47000 KB Output is correct
13 Correct 69 ms 45380 KB Output is correct
14 Correct 83 ms 45880 KB Output is correct

Subtask #5
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 39392 KB Output is correct
2 Correct 16 ms 39416 KB Output is correct
3 Correct 20 ms 39444 KB Output is correct
4 Correct 18 ms 39372 KB Output is correct
5 Correct 21 ms 39372 KB Output is correct
6 Correct 20 ms 39444 KB Output is correct
7 Correct 17 ms 39452 KB Output is correct
8 Correct 19 ms 39424 KB Output is correct
9 Correct 17 ms 39416 KB Output is correct
10 Correct 17 ms 39372 KB Output is correct
11 Correct 17 ms 39416 KB Output is correct
12 Correct 18 ms 39372 KB Output is correct
13 Correct 20 ms 39372 KB Output is correct
14 Correct 18 ms 39348 KB Output is correct
15 Correct 24 ms 39372 KB Output is correct
16 Correct 20 ms 39372 KB Output is correct
17 Correct 64 ms 56652 KB Output is correct
18 Correct 61 ms 56516 KB Output is correct
19 Correct 67 ms 56772 KB Output is correct
20 Correct 72 ms 56688 KB Output is correct
21 Correct 73 ms 56516 KB Output is correct
22 Correct 73 ms 56808 KB Output is correct
23 Correct 67 ms 45232 KB Output is correct
24 Correct 68 ms 45696 KB Output is correct
25 Correct 70 ms 45888 KB Output is correct
26 Correct 19 ms 39484 KB Output is correct
27 Correct 43 ms 41612 KB Output is correct
28 Correct 87 ms 45844 KB Output is correct
29 Correct 84 ms 45964 KB Output is correct
30 Correct 85 ms 46648 KB Output is correct
31 Correct 71 ms 47000 KB Output is correct
32 Correct 69 ms 45380 KB Output is correct
33 Correct 83 ms 45880 KB Output is correct
34 Correct 22 ms 39420 KB Output is correct
35 Correct 18 ms 39420 KB Output is correct
36 Correct 18 ms 39372 KB Output is correct
37 Correct 17 ms 39372 KB Output is correct
38 Correct 17 ms 39444 KB Output is correct
39 Correct 19 ms 39392 KB Output is correct
40 Correct 18 ms 39400 KB Output is correct
41 Correct 18 ms 39412 KB Output is correct
42 Correct 17 ms 39396 KB Output is correct
43 Correct 21 ms 39364 KB Output is correct
44 Correct 19 ms 39372 KB Output is correct
45 Correct 69 ms 56708 KB Output is correct
46 Correct 65 ms 56540 KB Output is correct
47 Correct 69 ms 56928 KB Output is correct
48 Correct 62 ms 45156 KB Output is correct
49 Correct 108 ms 45700 KB Output is correct
50 Correct 80 ms 45764 KB Output is correct
51 Correct 18 ms 39500 KB Output is correct
52 Correct 35 ms 41564 KB Output is correct
53 Correct 85 ms 45880 KB Output is correct
54 Correct 74 ms 45996 KB Output is correct
55 Correct 80 ms 46688 KB Output is correct
56 Correct 78 ms 46848 KB Output is correct
57 Correct 61 ms 45392 KB Output is correct
58 Correct 65 ms 45824 KB Output is correct
59 Correct 33 ms 41600 KB Output is correct
60 Correct 62 ms 45300 KB Output is correct
61 Correct 74 ms 45760 KB Output is correct
62 Correct 75 ms 46004 KB Output is correct
63 Correct 72 ms 45976 KB Output is correct
64 Correct 70 ms 45936 KB Output is correct
65 Correct 59 ms 46376 KB Output is correct
66 Correct 57 ms 46356 KB Output is correct
67 Correct 56 ms 46364 KB Output is correct
68 Correct 56 ms 46248 KB Output is correct
69 Correct 62 ms 46204 KB Output is correct
70 Correct 51 ms 46248 KB Output is correct